MOLGULA COMPLANATA. 47 



are more regular and less numerous than usual. The 

 folds are rather narrow and they have on each side 

 three or four membranous bars. The endostyle follows 

 the curvature of the folds and is very long, reaching 

 almost to the oral orifice. The oral lamina is not very 



/ 



wide, but gradually tapers from the mouth upwards. 

 The tentacular filaments are pretty-regularly uniform 

 in size and are simply pinnate. 



The alimentary canal (PL XXIV, figs. 1 and 3) 

 forms a simple, open loop, which does not extend 

 much more than half the width of the body. The 

 stomach appears to be quite small, and is not well 

 defined ; it is entirely concealed by the hepatic lobes, 

 of which, on the right, or outer, or exposed side there 

 are four, on the left, or inner, there is but one large 

 ovate mass. The component laminae, of a pale green 

 colour, are short, thick, and strongly defined. The 

 anal orifice (PI. XXIV, fig- 3) has a smooth reflected 

 border. 



The reproductive organs (PL XXIV, figs. 1-3) are 

 elongated, ovate, slightly arched bodies, with the ducts, 

 which issue from the narrow end, turned towards the 

 dorsal region, or in the opposite direction to that which 

 is usual. The right-hand organ is placed a little above 

 the extremity of the intestinal loop ; that on the left 

 side occupies relatively nearly the same position, and 

 is removed some distance from the cylindrical, cardiac 

 body which is about midway between it and the dorsal 

 margin, towards the lower end of the sac. This peculiar 

 org'an in connection with the heart is rather small; but 

 is considerably arched and has the ends irregularly 

 rounded. 



Numerous ova, in every stage of development, up to 

 the perfect tadpole larva (PL XXIV, fig. 6) occupied 

 the water-spaces between the branchial sac and man tie. 

 The larva is of a pale yellow colour ; the body much 

 elongated, with the anterior end a little produced, and 

 the extremity of the tail supplied with a fin-like 

 membrane. 



